Combination gas and coal fired furnace



Jan. 8 1924. 1,480,339

B. BANNISTER COMBINATION GAS AND COAL FIRED FURNACE 2 Sheets-Sheet 1 iwf- Patented Jan. 8, 1924.

nays-.NT Bumeran. or PITTSBURGH, rMen/Lv f f COMBINATION GAS A N'D COAKL FIR/ED FUENAGE.

Application aies september a, 192e. serial no. 408,905.

To all whom t may concern.:

Be it known that I, BRYANT BANNisrnn,

a citizen of the United States, and residentl of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Combination Gas and Coal Fired Furnaces, of which the following is a specification.

This invention relates to boiler furnaces,

and more particularlyto combined gas and coal tired boiler furnaces, and has for one of its objects the provision of such a furnace that may be fired with either gas or coal alone, or combined gas and coal.

Another and importantobject is to provide a furnace of this class having walls of improved and novel design that will allow for expansion and contraction without bul ing or breaking.

ill another object is to provide a furnace of this class having the gas burner and primary combustion chamber below the coal combustion chamber and floor level.

Heretofore furnaces of this class have been constructed for using gas and coal as fuel, but have proved unsatisfactory dueto the incomplete combustion of the gases before the entered the boiler tubes, and also due to t e fact that the furnace walls had a tendency to bulge inwardly and break due to the high temperature to which the inside furnace wall is subjected. The loutside of the same wall remaining comparatively cool, expansion takes place, tending to elongate the inner surface.

The present invention will eliminate the faults of the furnaces of this class heretofore constructed. The gas burner and primary combustion chamber being completely below the coal combustion chamber and floor level, permits the isolation of burners, clean-out doors, etc. from the operating door, and provides a long gas passage surroundedby refractory material for the completion of combustion after the gases leave the combustion chamber proper and before they enter the boiler tubes.

The walls of my improved furnace are inclined outwardly and, therefore, will not have a tendency to bulge inwardlyand Vbreak as do the walls of the furnaces heretofore constructed.

These and other objects and advantages will be more fully brou ht out in the following specification, and ilustrated in the accompanying drawings, in which- Flgure 1 1s a partial longitudinal sectional elevation through a boiler furnace embodylngwmy lnvention. p

*igure 2 is a sectional plan taken on the 60 line II-II of Figure 1.

Referring more particularl to the drawings, in which a single boilcr furnace is illustrated, the numeral 2 designates the it in which the furnace is built, and 3 desig- 0a nates the floor of the building or boiler room which is supported on I-beams 4 lextending from the side walls 5 of the room to the furnace upri ht supports 6.

The si e walls 7 andv 8 of the furnace which are composed of fire-brick or other refractory material, are inclined outwardly on an angle and are supported by a plurality of steel girder supports 9, so that the wei ht of the walls will always beso centered t at the tendency remains for the walls to rest upon the supporting steel work rather than to fall or bulge inwardly toward the furnace.

The gas combustion chamber 10 is built below the floor level and comprises a bottom 11 of refractory material having a dust collector 11 and supported on transverse irders 12 secured to the upright 6 and ividing and supporting wall 13. The chamber l0 has outwardly inclined side walls 14 and 15 of refractory material supported similarto the walls 7 and 8 by Steel girder supports 16. A suitableltop 17 is ormed over the admission end ofthe chamber 10 and may be of arched formation or any suitable construction as desired.

The side wall 8 of the main furnace construction extends downwardly an appreciable distance belowthe top 17 of the gas combustion chamber forming. a hanging ignition wall 18. Y

The side or front wall 14 extends up- Wardly an appreciable ydistance above the floor level forming the back wall 19 of a coal combustion chamber 20, which extends from the back wall 19 to the wall 7 The coal combustion chamber is adapted to be iredby a stokermechanism 21 adapted to receive coal through the entrance ort 22.105

and to discharge ashes into a. b er 23 which in turn dumps them into a car 24 running on track 24* in the pit 2 for removal.

A gas main 25 is shown on the outside of the rear wall 5, although it will be understood that thelocation of this main may be within the building if desired. The main 25 is provided with a' stand pipe 26 having a T-connection 27 adjacent its mp, and an outlet or clean-out door 28 at its bottom.

A gas feed pipe 29 'extends from the T-connection 27 to a burner 30 having a mushroom valve 31 for controlling the inlet of gas. A fan 32 supplies air under ressure to the air box 33 from which 1t is conveyed through pipe 34, havin a butteriy control valve 35 therein, to t e burner 30. The gas burner and its directly associated mechanism not being a art of this invention, willv not be describe further in detail.

Preferabl blast furnace gasf 'will be burned in t is furnace, although any other form of gas may housed. It is well known that blast furnace as carries a ,large guantity of dust an small particles of oreign matter with it and these particles have a tendency tolsettle and in time would clog and fill up the burners, pipes, andchambers. K However the stand pipe 26, dust collector 11, and suitable clean-out door or opening 37 'are provided to allow for the removal of such foreign matter'. Other clean-out doors or openings 38 and 39 are formed in the upper fortiori of the gas combustion chamber an lower portion of the coal combustion chamber, respectively, for

permitting access to these parts for cleaning and repairs.

While I have shown and described this invention as applied to a single boiler, it

I will be understoodthat it is adapted to be l coal may he appliedijto a battery of boilers, or single boiler, a`s`""desired, or to other uses than boiler-heating.

The operation of the furnace is as follows- Coal or other solid fuel is fed into the coal combustion chamber 20 throu h the stoker 21, and the products of com ustion are adapted to pass upwardl over` the wall 19 and into or around `the boi er tubes. The s flows from the main 25 down through t e stand pipe 26,-T-connection 27, feed pipe 29, to the burner 30, where it is mixed with air under pressure from fan 32 and flows into the combustionfchamber 10.where combustion is completed and the products of combustion pass upwardly between the walls 19 and 8 into or around the boiler tubes.

It will readily be apparent that either coal alone gas alone, or combined gas and used to lire this furnace. i combustion chambers are entirely `separated. Therefore, there will be no loss o-,f-heat when rect t e pro The' them for passage into or around the boiler tubes.

While I have illustrated and described one particular form of my invention, various modications may be made within the sco of the appended claims by those skilled 1n the art, without departing from the spirit of m invention.

I claim 1. Alcombined coal and gas fired boiler furnace comprising in combination, a coal combustion chamber abovethe floor level, a back wall along the rear end of said chamber and extending upwardly an appreciable distance so as to direct the products of combustion from said chamber against the boiler bein heated, a gas combustion chamber locate materially below the floor level at a wall, said c amber havin'g an ignition wall therein for retarding the passage of gas therethrough until combustion is established,

the portion of said gas combustion chamber chamber against the boiler being heated, a"

gas combustion chamber' extending substantially vertically from a point materially below the door level to the upper end of said back wall, thereby providing a lon `passage for the products of combustion, t e side walls` of said chambers being composed of refractory material and inclined outwardly, thus providing a constantly increasing cross sectional area towards the boiler to provide for the expansion `of the products of com` bustion, and also providing for the weight -of the walls to be so centered that they will not bulge inwardly;

3. In a combined coal andgas tired boiler furnace, a coal combustion chamber above the oor level, a back wall along the rear end of said chamber and extending u wardl an apreciable distance so `as to iucts ofy comb chamber algainst the boiler ing heated, a

gas combustion chamber extending substan` tially vertically l from a point materially below the door level to the upper end of said lback wall, thereby providing a long pas-v Eoint tothe rear of said back` tion from said gas combustion chamber,and suitablecleanout doors and apertures in both of said chambers. y

4. A combined coal and gas, fired boiler furnace com rising in combination, a coal combustion c amber above the iioor level, an automatic stoker for feeding coal into said chamber, and a back wall along the rear end of said chamber and extendin'g u wardly an ap reciable distance above sai stoker, and a apted to direct the products of combustion from said coal a ainst the boiler being heated, a gas com ustion chamber below the floor level at apoint to the rear of said backwall, said'chamber having an ignition wall ltherein for retarding the passagev of gas therethrough until combustion is established, the portion ofsaid gas com-- bustion chamber beyond said ignition wall 30 being of constantly increasing cross sec- Y wall, said c ,my name.

tional area toward the boiler to provide for the expansion of the gas as combustion takes place, and means for supplying air and gas to sald gas combustion chamber. y

5.- A combined coal and Lgas fredboiler furnace com rising in combination, a-coal combustion c amber above the ioor level, an automatic Stoker lfor feeding coal into said chamber and a back wall along the rear end of said chamber and extending upwardly an appreciable distance above Said stoker,and adapted to direct the products of combustion from said coal against the boiler being, heated, a gas combustion chamber below the ioor level at a point to the rear of said back therein for retarding the passage of gas therethrough until combustionis established, the portion of'said gas combustion chamber beyond' said ignition wall being of 'constantly increasing ycross sectional` area toward the boiler'to provide for theA expansion of the tas as combustionftakes place, and means or supplying a mixture of air and gas under pressure toA said gas combustion chamber, said combustion chambers being adapted to be operated separately or in unison.

In witness whereof 'I have hereunto signed BRYANT BANNISTER.,

amber .having an ignition wall 

